1. Technical Field
This invention relates to steerable vehicles for use on land and water. More particularly, this invention relates to a steerable personal vehicle which may ride on a plurality of runners.
2. Relevant Art
Current runner-mounted steerable personal vehicles, such as snowmobiles, snow sleds, water float sleds are provided with various rider-operated steering assemblies. The steering systems of such vehicles commonly include parallelogram steering linkages to provide adjustment to the camber angles of the runners, or skis. The camber angle of a runner refers to the angle of rotation of the runner relative to a vertical axis. For example, a skier may adjust the camber angles of his skis by turning the outside edge either upward or downward. Adjustment of the camber angle of a runner-mounted vehicle is important to the control and maneuverability of the vehicle. These parallelogram linkages usually include two transverse bars rotatably mounted to two vertical bars. The vertical bars are often shorter than the transverse bars. One of the transverse bars is typically affixed to the vehicle frame, while the other transverse bar is free to move. The free traverse bar is normally bound to each vertical bar only by its fastening point, and guided in movement by the other parts of the steering assembly. The fixed transverse bar supports a proportional amount of the total weight of the vehicle. The steering assemblies of such vehicles are designed to utilize the movement of these vertical and traverse bars. The fixed traverse bar is designed to flex, bend, or otherwise provide a non-rigid suspension in order to absorb shock transmitted from the terrain. When such a vertical bar flexes, an equal load is thereby distributed to the other vertical bar, but in an opposite direction. Similarly, when the free-moving transverse bar horizontally flexes, both of the vertical bars are thereby shifted from vertical alignment.
One of the drawbacks of such steering assemblies is that the parallelogram design does not lend itself to use in compact vehicles having low profiles. Indeed, the size, weight and complexity of such linkages make them inappropriate elements of a low-profile vehicle. Since the designs of current steering assemblies usually require the application of relatively large forces over short moment arms, these steering assemblies must include substantial structure in order to provide sufficient mechanical advantage. This substantial structure adds weight and complexity to the vehicle, thereby hindering the design of a compact personal vehicle.
It, therefore, is desirable to provide a steering assembly for a runner-mounted personal vehicle that provides for multi-axial steering of the vehicle, while also providing less size, weight and complexity than provided by current steering assemblies. It is also desirable to provide a runner-mounted personal vehicle, such as a sled, that is compact, lightweight and has a low profile.
It is an object of the present invention is to provide a steerable runner-mounted personal vehicle.
It is another object of the present invention is to provide a steerable runner-mounted personal vehicle having a multi-axial steering capability.
It is a further object of the present invention to provide a personal vehicle having a rider support that supports a rider in a prone position.
It is yet another object of the present invention to provide a steering assembly for a runner-mounted personal vehicle.
It is still a further object of the present invention to provide a sled mounted on a plurality of runners and being steerable about a plurality of axes.
More particularly, the present invention provides a runner-mounted personal vehicle, or sled, having a steering assembly operably connected to a frame. These two components are connected by a joint which allows rotation about multiple axes. The joint may include, for example, a universal joint, a constant velocity joint, or the like. A quick release device, such as a clevis separation pin, secures the frame to the joint, to thereby allowing quick separation of the steering assembly from the frame to facilitate transport of the vehicle when not in use.
The frame includes a rider support and a rear suspension. The rider support may carry a rider in a prone position, since the rider support may include a torso support, and a leg guard, which may include a thigh support, leg slings and shin supports. The rider support may allow the rider""s body to envelope partially the frame so as to provide a low profile to the rider-mounted vehicle. The rear suspension may include at least one rear runner, as well as a rear leaf spring which both connects the rear runner to the frame and absorbs shock from the terrain.
The steering assembly includes a rider interface, a front suspension, and a rotational transfer mechanism. The rider interface may include a set of handlebars, foot pedals or similar control devices well known in the art. The steering assembly also includes, linked to the joint, a steering head shaft which is also rotatably connected to a steering head. The rotational transfer assembly is operable connected to the steering head shaft, in order to transfer rotational force from the frame to the front runner(s), so as to adjust the camber angle of the front runner(s) in unison with rotational adjustments to the frame. More particularly, the rotational transfer assembly provides for any change in the lean of the rider support to be likewise transmitted to the front runner(s) so as to change the camber angle thereof This transmission of lean may be carried out by a gear set included in the rotational transfer mechanism. The front suspension is attached to the steering head and includes at least one front runner. The front suspension may also include a front leaf spring that serves both to connect the front runner(s) to the steering assembly and to absorb shock during operation of the vehicle.
The runners on which the personal vehicle of the present invention is mounted may be similar to either snow skis or water skis, depending on the intended use of the vehicle. The runners may also include tracks to which at least one wheel is attached. Thus, the runner-mounted personal vehicle of the present invention may be employed on snow, water and land.
Additional objects and advantages of the invention will become apparent to those skilled in the art from the following written description and the figures relating thereto.